Multiple chamber ball mill



April 28, 1959 C. lsARGEl-'eo` l MULTIPLE CHAMBER BALL MILL 4 sheets-Snead Filed May 5, 1955 FIGA NVENTORf.

April 28, 1959 c. BARGERo 2,884,209

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. y wmwllesm l April 28, 1959 c. vBARGERO 2,884,209 I MULTIPLE CHAMBER BALL MILL Filed May 5, 1955 4 sheets-sheet 4 MULTIPLE CHAMBER BALL MILL Camillo Bargero, Casale Monferrato, Italy Application May 5, 1955, Serial No. 506,285 Claims priority, application Italy May 6, 1954 Claims. (Cl. 241-153) This invention relates to a grinding mill for cement or lother materials of the type comprising a cylindrical drum rotating about a horizontal axis and enclosing grinding and refining bodies.

The grinding mill according to this invention is char.- terised in that it comprises an elongated cylindrical drum rotating about a horizontal axis, subdivided by radially directed longitudinal partitions into a plurality of chambers of circular sector-shaped cross section, enclosing grinding and refining bodies, the material being introduced into a set of chambers, the chambers being so interconnected that the material is caused to travel through part of the chambers from the inlet end to the opposite end of the grinding mill and through the other series of chambers in a contrary direction.

The invention shall be described with reference to the accompanying diagrammatical drawing, wherein:V

Figure 1 is a cross sectional view on line I-I of Figure 2 of a three-chamber drum,

Figure 2 is a crosssectional View of the drum on line II-II of Figure l,

Figure 3 shows a modification of a detail of Figure 1,

Figure 4 shows the chamber arrangement in a sixchamber grinding mill,

Figure 5 is an elevational view of a modiiied grinding mill construction,

Figures 6, 7 and 8 are sectional views on the lines Vl-VI, VII- VII and VIII-VIII, respectively, of Figure 5,

Figure 9 is an enlarged perspective view of one end of the grinding mill shown in Figure 5,

Figure is an elevational view of a grinding mill provided with \four grinding chambers according to a modified construction,

Figure ll shows the grinding mill according to Figure 10 with its ends in sectional view,

vFigure l2 is a sectional view on line XII-'-XH of Figure 10,

Figures 13 andv 14 are sectional views on lines XIII- XIII and XIV-XIV, respectively, of Figure 10,

Figure shows a modification of Figure l0,

v Figuresl 16 to 18 are sectional views on lines XVI-XVI, XVII-XVII and XVllIXVllL respectively, of Figure l5.

Referring to Figures l and 2, the grinding mill chiefly comprises an elongated drum 1 of circular cross section rotating about a horizontal axis XX and subdivided by radially directed longitudinal partitions 2, 3 and 4 into three chambers A, B, C.

The material is admitted through a hopper 5 provided with a discharge conduit 6 opening into a forebody or charging chamber 7 securedly connected to the drum 1. The charging chamber is provided with a iiange 8 preventing escape of the material falling along the conduit 6 before it enters the chamber A through holes 9.

A The material having entered the chamber A through the holes 9 travels longitudinally through the chamber -A 2,884,209 Patented Apr. 28,` 1959 ICC Z to the chamber B through holes 10 bored at the end re-` mote from the charging end in the radially directed 1ongitudinal partition 3 separating chamber A lfrom chamber B.

The material travels through the chamber B in a direction opposite the first mentioned direction and reaches the chamber C through holes 11 bored in the end of the radially directed longitudinal partition 2 separating the chambers B and C adjacent the charging end.

The material then travels lengthwise through the chamber C in the same direction as through the chamber A and is discharged to the outside through holes 12 bored in the end wall 13 of the drum 1.

The chambers enclose balls 14 decreasing in size from the chamber A towards the chamber C for coarse and fine grinding.

ln the modified construction shown in Figure 3 the forebody is arranged within the drum.

Figure 4 shows the chamber arrangement when the chambers are in the number of six. The material is fed to the chambers A, travels through chambers B and C in parallel and is discharged from the chambers C still in parallel.

The grinding mill shown in Figures 5 to 9 comprises a cylindrical casing 1 closed at its front ends, provided with openings 22, 23 for inlet and outlet of the material and a gear 24 through which it is rotated.

The casing 1 is longitudinally subdivided into three sector shaped chambers A, B and C of a width of about 108, 90, 162, respectively, in which the material is successively ground and ultimately finely ground to the desired fineness by the grinding bodies enclosed within the chambers.

The material is fed to the rs't chamber A through the opening 22 by a scroll not shown on the drawing, the finely ground material being discharged from the third chamber C through the opposite opening 23.

The grinding mill is rotated in the direction shown by the arrow 28, the longitudinal travel of the material with-y in the successive grinding chambers taking place in chamber A from the inlet 22 towards the outlet 23, in chamber B in an opposite direction and chamber C in the same direction as in chamber A by effect of the contin' nous supply of material through the opening 22.

A communication is established between chambers A- and B at the end of the grinding mill near the outlet opening 23 and at its central portion for the material having undergone the first grinding step. Communica tion is established through grids 25 provided in the casing at chamber A, and having arranged thereabout exter nal semi-circular channels 26 ending by openings 27 for discharging the material into chamber B.

An annular box 30 is arranged at the end of the grind-v ing mill near the inlet opening 22 about the casing. Af grid 29 is provided within the box 30 in the wall of the chamber B, together with a transverse partition 31 and a sieve 32.

The material issuing from chamber B through the grid 29 reaches the sieve 32. The insutliciently ground portions are not passed by the meshes of the sieve and are returned through an external conduit 33 to lchamber A for completing grinding, while the fine material passed by the sieve 32 comes past the latter into contact with the outer wall of the box 30 and is discharged through an opening 34 into the line grinding chamber C.

The intermediate channel 26 directly conveys the ma; terial having undergone a suiiicient grinding in the first chamber to the second chamber without the material travelling uselessly through the remainderl of the'rst chamber and avoiding any clogging, whereby the output of the grinding mill isimproved. Y y

In the grinding mill construction shown in Figures l0 to 14 the'casing 1 is subdivided lengthwise into four sector-shaped chambers. In the chambers A and B the first and second grinding step, respectively, are carried out. The angular Width of these chambers is 108 and 90, respectively. The chambers C serving for fine grinding are each 81 wide. A helical conduit 40 and a plurality of semi-circular boxes 41 are provided around the `casing 1. The boxes are arranged at intermediate positions and at the end near the outlet opening for the material. A sieve 42 is arranged within each semi-circular box 41, a grid 43 being provided within the box at the chamber A. The material having undergone a first grinding step is passed by the grid 43 and reaches the sieve 42. Its coarser portions are conveyed towards opening 44 by which they are discharged into the chamber B in which they undergo a second grinding step. The ner portions passed by the sieve are conveyed along the helical conduit 40 at the end of which near the front end 22 of the grinding mill they are discharged through two openings 45 into either chamber C for fine grinding.

A grid 46 is provided at the end of chamber B near the inlet opening 22 to allow the material having travelled through the whole of chamber B to reach either chamber C through the openings 45. A box 47 forming a circular conduit is provided around the grid 46.

In the modified construction shown in Figures 15 to 18 the grinding mill is subdivided into four sectors as in the previously described construction. The casing comprises three semi-circular boxes 50 spaced over the length of the grinding mill enclosing at the wall of chamber A grids 51 through which the material which has been sufficiently ground can escape and reach through openings 52 the next chamber B.

The central portion ofthe casing further comprises a semi-circular box 53 and an external helical conduit 54 ending at the front end near the inlet opening 22.

A sieve 55 and a grid 56 in the wall of the chamber B are arranged within the semi-circular box 53. The material passed by the grid 56 which is too coarse for the meshes of the sieve 55 is returned through an opening 57 to the chamber B for completing grinding, while the material passed by the sieve 55 is conveyed by the helical conduit 54 towards the inlet end of the grinding mill and admitted through openings 58 into either chamber C for fine grinding.

The first passage means forming part of my novel apparatus as defined in the appended claims consist in the embodiment shown in Figs. 5-9 of grid 25, semicircular channel 26 and opening 27, all located in an end portion of the drum, in the embodiment shown in Figs. 10-14 of grid 43, semi-circular box 41 and opening 44, all located in an end portion of the drum, and in the embodiment shown in Figs. 15-18 of grid 51, semicircular box S and opening 52, all located in an end portion of the drum.

The second passage means forming part of my novel apparatus as defined in the appended claims consist in the embodiment shown in Figs. -9 of grid 25, semicircular channel 26 and opening 27, all located in an intermediate portion of the drum, in the embodiment shown in Figs. -14 of grid 43, semi-circular box 41 and opening 44, all located in intermediate portions of the drum, and in the embodiment shown in Figs. -18 of grid 51, semi-circular box 50 and opening 52, al1 located in intermediate portions of the drum.

The third passage means forming part of my novel apparatus as defined in the appended claims consist in the embodiment shown in Figs. 5-9 of grid 29, sieve 32, a duct formed by box 30 and partition 31, having an opening 34 into the chamber C for finest matter as well as of an external conduit 33 to return coarser matter for regrinding into the first grinding chamber, in the embodiment shown in Figs. 10-14 of grid 46, box 47 and openings 45, and in the vembodiment shown in Figs. 15- 18 of grid 46, box 47 and openings 58.

The fourth passage means forming part of my novel apparatus as defined in the appended claims consist in the embodiment shown in Figs. 10-14 of sieve 42, helical conduit 4th and openings 45, and in the embodiment shown in Figs. 15-18 of sieve 55, semi-circular box 53, helical conduit 54 and openings 57 and 58.

My improved grinding mill is simple in construction, high output and low power consumption.

What I claim is:

l. In a -grinding apparatus, in combination, an elongated hollow grinding drum adapted to be rotated about its axis; partition means carried by said drum in the interior thereof and dividing the interior of said drum into a first grinding chamber, a second grinding chamber and at least one final grinding chamber, said chambers being distributed about and extending substantially parallel to the drum axis; grinding means located in said chambers for grinding material therein; first passage means providing communication between an end portion of said first chamber and said second chamber for providing a path for material of a given fineness to said second chamber only after it has moved along substantially the entire length of said first chamber; second passage means providing communication between an intermediate portion of said first chamber spaced from the both ends of said first -chamber and said second chamber for providing a path of ow from said first chamber to said second chamber of material of said given fineness before said latter material has moved along the entire length of said first chamber; and third passage means providing communication between an end portion of said second chamber and said final chamber for providing a path for material of extra fineness to said final chamber only after it has moved along substantially the entire length of said second chamber.

2. In a grinding apparatus, in combination, an elongated hollow grinding drum adapted to be rotated about its axis; partition means carried by said drum in the interior thereof and dividing the interior of said drum into a first grinding chamber, a second grinding chamber and at least one final grinding chamber, said chambers being distributed about and extending substantially parallel to the drum axis; grinding means located in said chambers for grinding material therein; first passage means providing communication between an end portion of said first chamber and said second chamber for providing a path for material of a given fineness to said second chamber only after it has moved along substantially the entire length of said first chamber; second passage means providing communication between an intermediate portion of said first chamber and said second chamber for providing a path of flow from said first chamber to said second chamber of material of said given fineness before said latter material has moved along the entire length of said first chamber; and third passage means for providing communication between an end portion of said second chamber and said final chamber for providing a path for material of extra fineness to said final chamber only after it has moved along substantially the entire length of said second chamber, said third passage means also including a path for material of said given fineness from said end portion of said second chamber to said first chamber.

3. In a grinding apparatus, in combination, an elongated hollow grinding drum adapted to be rotated about its axis; partition means carried by said drum in the interior thereof and dividing the interior of said drum into a first grinding chamber, a second grinding chamber and at least one final grinding chamber, said chambers being distributed about and extending substantially parallel to the drum axis; grinding means located in said chambers for grinding material therein; first passage means providing communication between an end portion of said first chamber and said second chamber for providing a path for material of a given fineness to said second ,5 chamber only :after it has moved along substantially the entire length of said first chamber; second passage means providing communication between an intermediate portion of said first chamber and said second chamber for providing a path of flow from said first chamber to said second chamber of material of said given fineness before said latter material has moved along the entire length of said first chamber; third passage means providing communication between an end of said second chamber and said final chamber for providing a path for material of extra fineness to said final chamber only after it has moved along substantially the entire length of said second chamber; and fourth passage means providing communication between said first passage means, said second passage means and said third passage means for providing ya path for material of said yextra fineness from said first chamber directly to said final chamber.

4. In a grinding apparatus, in combination, an elongated hollow grinding drum adapted to be rotated about its axis; partition means carried by said drum in the interior thereof and dividing the interior of said drum into a first grinding chamber, a second grinding chamber and at least one final grinding chamber, said chambers being distributed about Iand extending substantially parallel to the drum axis; grinding means located in said chambers for grinding material therein; rst passage means providing communication between an end portion of said rst chamber and said second chamber for providing a path for material of a given neness to said second chamber only after it has moved along substantially the entire length of said first chamber; sec ond passage means providing communication between an intermediate portion of said first chamber and said second chamber for providing a path of flow from said first chamber to said second chamber of material of said given fineness before said latter material has moved along the entire length of said first chamber; third passage means providing communication between an end of said second chamber and said final chamber for providing a path for material of extra fineness to said final chamber only after it has moved along substantially the entire length of said second chamber; and fourth passage means providing communication between said first passage means, said second passage means and said third passage means for providing a path for material of said extra fineness from said first chamber directly to said final chamber, said fourth passage means and said third passage means interconnected to one another for passing said material of said extra fineness through 'an orifice into said final chamber.

5. In a grinding apparatus, in combination, an elongated hollow grinding drum adapted to be rotated about its axis; partition means carried by said drum in the interior thereof and dividing the interior of said drum into a first grinding chamber, a second grinding chamber and at least one final grinding chamber, said chambers being distributed about and extending substantially parallel to the drum axis; grinding means located in said chambers for grinding material therein; first passage means providing communication between an end portion of said first chamber and said second -chamber for providing a path for material of .a given fineness to said second chamber only after it has moved along substantially the entire length of said first chamber; second passage means providing communication between an intermediate portion of said rst chamber Iand said second chamber for providing a path of ow from said first chamber to said second chamber of material of `said given fineness before said latter material has moved along the entire length of said first chamber; third plassage means providing communication between :an end of said second chamber and said final chamber for providing a path for material of extra fineness to said final chamber only after it has moved along substantially the entire length of said second chamber; and fourth piassage means providing communication between an intermediate portion of said second chamber and said third passage means for providing .a path for material of said extra fineness from said second -chamber directly to said final chamber, said fourth passage means also providing a passage for said material of said given fineness to said second chamber for regrinding.

References Cited in the le of this patent UNITED STATES PATENTS 420,934 Graepel Feb. l1, 1890 1,646,532 Goebels Oct. 25, 1927 FOREIGN PATENTS 85,054 AllStria Aug. 10, 1921 

